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Synlett 2005(19): 2931-2934  
DOI: 10.1055/s-2005-921905
LETTER
© Georg Thieme Verlag Stuttgart · New York

Azacalix[n]arenes with -NH- Amino Group: NH···OCH3 Interaction-Assisted Synthesis, Structure, and Reactivity

Wataru Fukushima, Takaki Kanbara*, Takakazu Yamamoto*
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
Fax: +81(45)9245976; e-Mail: tkanbara@res.titech.ac.jp;
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Publication History

Received 13 September 2005
Publication Date:
04 November 2005 (online)

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Abstract

Designed intramolecular NH···OCH3 hydrogen bonding interaction induced facile formation of new azacalix[n]arenes ­(arene unit: n = 4, 6, 8) with bridging -NH- amino group by ­palladium-catalyzed aryl amination. Reaction of the -NH- group with acetic anhydride gave corresponding N-acetylated derivatives.

Key words

macrocycles - cyclizations - aminations - palladium - ­arenes

7

Experimental Procedure.
A mixture of 1,3-dibromo-4,6-dimethoxybenzene (296 mg, 1 mmol) and 1,3-phenylenediamine (108 mg, 1 mmol) was dissolved in toluene (15 mL). Sodium-tert-butoxide (288 mg, 3 mmol), tris(dibenzylideneacetone)dipalladium(0)
[Pd2 (dba)3; 46 mg, 0.05 mmol], and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (XANTPHOS; 58 mg, 0.1 mmol) were added to the solution. The reaction mixture was stirred at 100 °C for 5 d under N2. After cooling to r.t., the mixture was quenched by the addition of an aqueous solution of EDTA-2K (ca. 100 mL), and the product was extracted with CHCl3. The crude product was purified by column chromatography on silica gel (yield: 1, 19%; 2, 9%; 3, 1%).
Macrocycle 1 (m = 2, arene unit n = 4): FAB-MS: m/z = 485 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.28 (s, 2 H), 7.11 (s, 2 H), 7.09 (t, J = 7.8 Hz, 2 H), 6.55 (s, 2 H), 6.36 (d, J = 7.8 Hz, 4 H), 5.67 (br, 4 H), 3.79 (s, 12 H). 13C NMR (100 MHz, CDCl3): δ = 145.2, 144.1, 130.4, 126.4, 111.1, 109.2, 102.9, 99.0, 56.8.
Macrocycle 2 (m = 3, arene unit n = 6): FAB-MS: m/z = 727 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.32 (s, 3 H), 7.00 (t, J = 7.7 Hz, 3 H), 6.96 (s, 3 H), 6.53 (s, 3 H), 6.26 (d, J = 7.8 Hz, 6 H), 5.78 (s, 6 H), 3.78 (s, 18 H). 13C NMR (100 MHz, CDCl3): δ = 146.2, 146.0, 130.0, 125.0, 114.9, 108.4, 102.3, 98.1, 56.4.
Macrocycle 3 (m = 4, arene unit n = 8): FAB-MS: m/z = 969 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.27 (s, 4 H), 7.06 (s, 4 H), 6.74 (br, 4 H), 6.46 (br, 4 H), 6.41 (br, 8 H), 5.73 (br, 8 H), 3.78 (s, 24 H).

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Preparation of the macrocycles 1-3 using 1,3-dibromobenzene and 4,6-dimethoxy-1,3-phenylenediamine was carried out in analogy with ref. 7 (yield: 1, 23%; 2, 13%; 3, 3%).

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Preparation of macrocycles 4 and 5 was carried out in analogy with ref. 7 using 1,3-dibromo-4,6-dihexyloxybenzene and 1,3-phenylenediamine (yield: 4, 12%; 5, 3%).
Macrocycle 4 (m = 2, arene unit n = 4): FAB-MS: m/z = 765 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.31 (s, 2 H), 6.97 (br t, 4 H), 6.52 (s, 2 H), 6.28 (d, J = 8.6 Hz, 4 H), 5.78 (s, 4 H), 3.89 (t, J = 8.8 Hz, 8 H), 1.72 (q, J = 9.1 Hz, 8 H), 1.30 (m, 24 H), 0.88 (br t, 12 H). 13C NMR (100 MHz, CDCl3): δ = 145.6, 145.4, 134.2, 132.5, 123.1, 101.0, 99.9, 87.7, 69.9, 31.6, 29.4, 25.7, 22.6, 14.1.
Macrocycle 5 (m = 3, arene unit n = 6): FAB-MS: m/z = 1147 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.31 (s, 3 H), 6.96 (br, 6 H), 6.55 (br m, 9 H), 5.75 (br, 6 H), 3.91 (br, 12 H). 1.75 (br, 12 H) 1.31 (br, 36 H), 0.88 (br, 18 H). 13C NMR (100 MHz, CDCl3): δ = 145.5, 145.2, 129.8, 127.4, 126.2, 101.2, 100.9, 94.0, 69.9, 31.6, 29.4, 25.8, 22.7, 14.1.

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Crystallographic data for 6: C22H22Br2N2O4, M = 538.23, triclinic, space group P1bar, a = 7.924 (2), b = 10.581 (5), c = 13.436 (4) Å, α = 98.971 (12)°, β = 94.465 (12)°, γ = 106.014 (13)°, V = 1060.9 (6) Å3, Z = 2, D calcd = 1.685 g cm-3, µ(MoKα) = 38.64 cm-1, T = 113 K, F(000) = 540, 14632 reflections measured, 4397 unique, 3515 observed [I > 3σ(I)], 293 variables, R(F 0) = 0.049, R w (F 0) = 0.063, GOF = 1.087. Crystallographic data for 1·MeCN: C30H31N5O4, M = 525.61, triclinic, space group P1bar, a = 10.302 (7), b = 11.632 (8), c = 13.260 (8) Å, α = 100.305 (2)°, β = 106.047 (7)°, γ = 114.926 (7)°, V = 1302.9 (14) Å3, Z = 2, D calcd = 1.340 g cm-3, µ(MoKα) = 0.91 cm-1, T = 113 K, F(000) = 556, 19554 reflections measured, 5598 unique, 2971 observed [I > 2σ(I)], 383 variables, R(F 0) = 0.059, R w (F 0) = 0.070, GOF = 1.128.

13

Preparation of compound 6 was carried out in analogy with ref. 7 using 1,3-phenylenediamine with 2 equiv of 1,3-dibromo-4,6-dimethoxybenzene (55% yield).
Compound 6: FAB-MS: m/z 539 [M + 2 + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.44 (s, 2 H), 7.13 (t, J = 8.4 Hz, 1 H), 6.59 (s, 1 H), 6.57 (d, J = 8.4 Hz, 2 H), 6.55 (s, 2 H), 5.72 (s, 2 H), 3.87 (s, 12 H). 13C NMR (100 MHz, CDCl3): δ = 150.5, 149.7, 144.6, 130.1, 127.0, 122.0, 109.7, 105.7, 102.0, 98.2, 57.2, 56.0.

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Macrocycle 1 (48 mg, 0.1 mmol) was dissolved in Ac2O (1 mL). The reaction mixture was refluxed for 4 h. The reaction mixture was filtered and the precipitate was washed with H2O and MeOH (7: 92% yield). Reaction of 2 with Ac2O was carried out analogously (8: 87% yield).
Macrocycle 7: FAB-MS: m/z = 653 [M + H]+. 1H NMR (400 MHz, CDCl3): δ = 7.98 (m, 10 H), 7.06 (br, 2 H), 4.37 (br, 12 H), 2.71 (br, 12 H).
Macrocycle 8: FAB-MS: m/z = 979 [M + H]+. 1H NMR (400 MHz, DMSO-d 6, 100 °C): δ = 7.31 (br, 3 H), 7.18 (br, 6 H), 7.02 (br, 6 H), 6.85 (s, 3 H) 3.88 (s, 18 H), 1.81 (s, 18 H).

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Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre; publication numbers CCDC 282778 (1) and 282779 (6).